diff --git a/src/lib.rs b/src/lib.rs
index d218a83..a98a0af 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -121,7 +121,7 @@ pub struct Cert {
     pub authenticity: AuthCert,
     pub membership: MembershipProof,
     pub salt: Salt,
-    pub hash: Vec<u8>,
+    pub hash: [u8; 32],
 }
 
 impl Cert {
@@ -135,7 +135,7 @@ impl Cert {
             authenticity: auth,
             membership: mem,
             salt: salt,
-            hash: h.finalize().to_vec(),
+            hash: h.finalize().into(),
         }
     }
 }